How to install gtop (graphical top) an advanced text UI system monitor on Ubuntu 18.04 or similar

top, atop, iotop etc are all very good and well known system monitoring tools which run perfectly via simple terminal sessions (no X server or mouse required). But sometimes you would prefer some graphical representation added to it. Some graphs. There comes “gtop” handy. Its still a text UI top-a-like tool. However they added some clever ASCII graphics to it. Since i learned about this nice tool, i dont want to miss it! check it out.